Electromagnetic cutting device with change-over switch

ABSTRACT

Cutting device for thread, rope, wire and the like actuated electromagnetically with means for holding an end of the material to be cut during and after cutting, the cutting movement being automatically repeated if the material is not cut through completely on the previous movement.

United States Patent Inventor Kurt Hess Canton, Luzern, SwitzerlandApp]. No. 822,249 Filed May 6, 1969 Patented Mar. 16, 1971 AssigneeHeberlein & C0. AG

Wattwil, Switzerland Priority May 13, 1968 Switzerland 7071/68ELECTROMAGNETIC CUTTING DEVICE WITH CHANGE-OVER SWlTCI-I 5 Claims, 5Drawing Figs.

U.S. Cl. 83/576, 83/577, 83/580 Int. Cl B26d l/09 Field of Search83/575,

[5 6] References Cited UNITED STATES PATENTS 7/1957 Leirer 4/1967 Davis,Jr. et a1. 5/1967 Felix 12/1967 Frei FOREIGN PATENTS 1,068,228 5/1967Great Britain Primary Examiner-William S. Lawson Attorney-Ward,McElhannon, Brooks & Fitzpatrick ABSTRACT: Cutting device for thread,rope, wire and the 4 83/575X 83/575X 83/575X 83/577X like actuatedelectromagnetically with means for holding an end of the material to becut during and after cutting, the cutting movement being automaticallyrepeated if the material is not cut through completely on'the previousmovement.

ELEQTRGMAGNETIIC CUTTING DEVICE WITH CHANGE-OVERSWHTCH The presentinvention relates to a cutting device for thread, rope or wire and thelike, and includes a cutter which is actuated by the armature of anelectromagnet or solenoid.

in order to effect reliable and precise cutting of textile threads,ropes or wires, for example, apparatuses are known in which two cuttingedges which are moved towards each other in the manner of scissors, andin which the material remaining after the cut, is caught or pinched fastby a special device separate from the cutting device.

In a further known cutting apparatus, a bank of knives rigidly fixed onthe armature of an electromagnet and which has a passage for thematerial to be cut arranged within the cutter, is lead horizontally andwith a traction movement against a cutting edge which is horizontallystationary, together with the passing material to be cut. The cutter isthus vertically pressed against the surface of the knife bank by apressure spring acting from above so that, as the length of the path ofmovement of the knife bank increases until it meets with the cuttingedge of the cutter, the pressure of the cutter against the knife bankalso increases so that the pressure is at its maximum when cutting iseffected.

The disadvantage of this apparatus consists in that, under certaincircumstances, the knife bank may draw the material to be cut out of itsnormal running path so that it forms an angle with the cutting and knifeedges, whereby, instead of cutting the material, it may pinch the latterbetween the cutter and knife edges. Furthermore, because of defects suchas knots, differences in diameter and so on, which occur in the materialto be cut, it may not be possible to advance the same uniformly betweenthe knife bank and the cutter edge because the cutter edge is liftedfrom the knife, and this may also lead to pinching of the material tobe. cut.

In another known apparatus, the separation of the threads is effected bythe armature of a solenoid by centrally attracting the armature whichcan be swiveled about one end thereof, whereby a cutter fixed on theother end of the armature strikes a conical anvil with a cutting edge, athread being led over the anvil by means of a thread leading groove. Thecutter is situated on one arm of a U-shaped device on the other arm ofwhich is provided a thread pinching device, which, acting simultaneouslywith the cutter, fixes the thread on a further anvil. After terminationof the cutting step, the cutter is lifted away from the anvil togetherwith the thread pincher by a retraction spring arranged above the swivelcenter of the armature.

This apparatus also presents the disadvantage that, by hammerlikeadvancing of the cutter as well as by the cutting faces gliding pasteach other in an oblique plane, respectively,

pinching of the material to be cut may also occur within a wedge-shapedgrooveof the anvil. Moreover, with continuously moving armatures, thereis the danger of armature vibration which is caused by the tractionspring as well as by saturation of the magnetic field, being transferredto the cutter. Furthermore, in continuous armature movement, much of thecutting force is absorbed by the preceding friction between cutter andknife bank, so that the remaining cutting force of the armature isreduced for the actual cutting operation.

I have conceived by my present invention, a cutting device whicheliminates the foregoing difficulties and disadvantages by means of acutting device which is actuated electromagnetically, the cuttingmovement being automatically repeated, should the material not have beencut through completely.

Accordingly, I provide a cutting device for thread, rope, wire or thelike, with a cutter actuatable by the armature of an electromagnet,comprising: a slidable and swivellable cutter which, at a freeextremity, cooperates with a coupling part rigidly connected with thearmature, and which cooperates at its other end with a fixed knife. Ifurther provide a retraction spring for applying a force between thesliding cutter and the stationary knife, as well as for applying aretractive force on the knife and on the armature.

As a further feature of my invention, I provide means for pinching thematerial to be out just prior to the cutting and for retaining an end ofthe material in that condition as long as desired after cutting occurs.Such means may include a member which shifts with the cutter but whichprecedes it during the protraction excursion; and a pad against whichsuch member presses the material to be cut just prior to the actualcutting.

Another feature of the invention resides in the provision of aresistance which is normally bridged by the solenoid induction coilcircuit; but which can be placed in series with the coil by a switch inthe bridging circuit. The various parts are so ar ranged that bridgingis interrupted just prior to completion of the protraction excursionwherefor pinching and holding of the material is effected only by aholding current. However, if the material is not cut on the firstprotraction, its thickness causes an airgap between the coil and core ofthe solenoid, and this gap, together' with the low holding current andthe retraction spring, return the cutter to its starting position fromwhich it again strikes at the material and continues to dose untilcutting is achieved after which it remains protracted to hold thematerialend. r

Further specific features and advantages of the invention will behereinafter more fully set forth with reference to the annexed drawings,showing a presently preferred embodiment of the invention and certainmodifications thereof, in which:

FIG. 1 is a side elevational view of the apparatus of the presentinvention in its normal at rest position;

FIG. 2 is a plan view of a part of the cutting device in normalposition;

FIG. 3 is a view similar to that of FIG. 1, but showing the apparatus incutting position;

FIG. 4 is a plan view similar to that of FIG. 2, but showing the cuttingdevice in cutting position; and

FIG. 5 is a circuit diagram of the electrical system.

The cutting device shown in FIGS. 1 and 2 consists of a housing 1 inwhich a pot magnet 2 and tubular coil 3 are arranged. An armature 4 witha conical attraction surface 5 in which a pin 6 is fixed by means ofscrews is positioned for axial movement in the coil recess. The enlargedend 7 of the pin 6 has a central opening 8 for vertically swivellablearrangement therein of a cutter 9, and of a pinching member 10 which isrigidly fixed on the upper face of the cutter 9. The cutter 9 is drawnagainst a knife 14 by a retraction spring 11 which, by one of itsextremities, is attached to a hook 12 provided on the housing 1. Duringadvancing of the armature 4 and, therefore, of the cutter 9 when thecoil is energized, the pressure against the knife bank 13 and the knife14 provided thereon is increased as the knife comes forward due to theeffect of the spring ill. On one side, the knife 14 is provided with anopening 15 for passage of the material 16 to be cut. During the cuttingprocedure, the member 10 for pinching the material to be cut, and whichslightly protrudes over the cutting edge of the cutter 9, presses thematerial 16 to be cut against an elastic pad 17 which is fixed on therear wall 19 of the housing, and there maintains the material 16 to becut in position.

After cutting has been effected, the cutter 9, together with the member10, is maintained in the cutting position by the armature 4 and the pin6 as shown in FIGS. 3 and 4, this condition being maintained as long asthe current circuit is closed.

After reinserting the material 16, the cutter 9 and member 10 may bereturned to normal position by interrupting the current circuit.

The protractive movement of the armature 4 together with the pin 6 andthe cutter 9 together with the material pinching member 10 is effectedas follows:

On the free end of armature l, a metal ring 26 is provided with aninsulating ring 27 lining the inner surface thereof. In its normalposition, the contact point of a switching contact 25 is in contact withthe metal ring 26, so that the resistance 2a in the current supply linefor the coil 3 is coil However, in a certain position of the armature 4within the coil 3, contact point of the switch contact 25 comes intocontact with the insulating ring 27, wherefor the bridging of theresistance 24 is interrupted, and the coil 3 is connected in series withthe resistance 24. In this circumstance, only a relatively small holdingcurrent flows through the coil 3, and the armature 4 is, therefore,during the last portion of its protractive excursion, moved only by theholding current and its mass acceleration.

The advantage of the above lies in thefact that the armature 4, with thecutter 9 and the member 10, is maintained in protracted position by onlya very slight holding current, while the cut material is pinched betweenthe member 10 and pad 17 until the current circuit is completelyinterrupted by the switch 28 (FIG.

When a very thick or very hard material is to be cut, the holdingcurrent is not sufficient to hold the armature 4 with the cutter 9 andthe member in the cutting position of FIGS. 3 and 4 because of theremaining airgap between the armature 4 and core cap 20. Accordingly,the armature 4 is retracted into its original position (FIGS. 1 and 2)by the spring 11, and the resistance 24 connected in series with thecoil 3 is again bridged by the switch contact 25, wherefor full currentflows again in coil 3, whereby the cutting procedure is automaticallyrepeated until the material is completely cut through.

From the foregoing description, it will be seen that an essentialadvantage of the cutting device of the present invention consists inthat the cut may be effected in all positions of the thread; that, by aseries circuit of the induction coil with a resistance, an undesirableheating of the coil is prevented; and that, when a thick or hardmaterial is incompletely cut, the cutting is automatically repeateduntil the material is completely cut through.

I believe that the construction and operation of my contribution willnow be fully understood, and that its advantages will be appreciated bythose persons skilled in the art.

I claim:

1. Cutting apparatus for thread, rope and wirelike material with acutter actuated by the armature of an electromagnet, characterized by acutter having a free extremity, a coupling member rigidly connected tosaid armature, means for mounting said cutter on said coupling memberfor horizontal sliding movement and for vertical swiveling movement, afixed knife cooperating with said cutter to cut material when saidcutter is advanced, and a traction spring attached to the cutter forexerting pressure between said cutter and the rigid knife, as well as aretracting force acting on the cutter and the armature.

2. Cutting apparatus for thread, rope and wirelike material with acutter actuated by the armature of an electromagnet, characterized by acutter having a free extremity, a coupling member rigidly connected tosaid armature, means for mounting said cutter on said coupling memberfor sliding movement in one direction and for swiveling movement, afixed knife cooperating with said cutter to cut material when saidcutter is advanced, and a traction spring attached to the cutter forexerting pressure between said cutter and the rigid knife, as well as aretracting force acting on the cutter and the armature, a materialpinching means comprising a member rigidly connected with the cutter formoving therewith, and a pad fixed opposite the end of said member andagainst which pad the member presses the cut material after cutting hasbeen effected.

3. Cutting apparatus for thread, rope and wirelike material with acutter actuated by the armature of an electromagnet, characterized by acutter having a free extremity, a coupling member rigidly connected tosaid armature, means for mounting said cutter on said coupling memberfor sliding movement in one direction and for swiveling movement, afixed knife cooperating with said cutter to cut material when saidcutter is advanced, and a traction spring attached to the cutter forexerting pressure between said cutter and the rigid knife, as well as aretracting force acting on the cutter and the armature, contact meansarranged at one end of the armature and comprising a conductive memberand an insulating member for actuatin a switch member to effect a seriesconnection of the induc ion coil of the electromagnet with a resistancebefore the armature reaches the full limit of its protrative excursion.

4. Cutting apparatus according to claim 3, characterized in that theinduction coil, the armature and the traction spring are so selectedthat, when the coil is connected in series with said resistance, acurrent flows in the coil which, when the material to be cut has beenseparated completely, is just suffcient to hold fast the armature andthe cutter in close contact with the magnet core whereas, if thematerial has not been cut through completely, the current is notsufficient because of the airgap existing due to the thickness of theuncut material between the armature and the core, wherefore the armatureand the cutter are retracted into their original position by the springand a repetition of the cutting movement occurs,

5. Cutting apparatus according to claim 1, characterized by aring-shaped knife opened to one side which is arranged to cooperate withthe moveable cutter.

1. Cutting apparatus for thread, rope and wirelike material with acutter actuated by the armature of an electromagnet, characterized by acutter having a free extremity, a coupling member rigidly connected tosaid armature, means for mounting said cutter on said coupling memberfor horizontal sliding movement and for vertical swiveling movement, afixed knife cooperating with said cutter to cut material when saidcutter is advanced, and a traction spring attached to the cutter forexerting pressure between said cutter and the rigid knife, as well as aretracting force acting on the cutter and the armature.
 2. Cuttingapparatus for thread, rope and wirelike material with a cutter actuatedby the armature of an electromagnet, characterized by a cutter having afree extremity, a coupling member rigidly connected to said armature,means for mounting said cutter on said coupling member for slidingmovement in one direction and for swiveling movement, a fixed knifecooperating with said cutter to cut material when said cutter isadvanced, and a traction spring attached to the cutter for exertingpressure between said cutter and the rigid knife, as well as aretracting force acting on the cutter and the armature, a materialpinching means comprising a member rigidly connected with the cutter formoving therewith, and a pad fixed opposite the end of said member andagainst which pad the member presses the cut material after cutting hasbeen effected.
 3. Cutting apparatus for thread, rope and wirelikematerial with a cutter actuated by the armature of an electromagnet,characterized by a cutter having a free extremity, a coupling memberrigidly connected to said armature, means for mounting said cutter onsaid coupling member for sliding movement in one direction and forswiveling movement, a fixed knife cooperating with said cutter to cutmaterial when said cutter is advanced, and a traction spring attached tothe cutter for exerting pressure between said cutter and the rigidknife, as well as a retracting force acting on the cutter and thearmature, contact means arranged at one end of the armature andcomprising a conductive member and an insulating member for actuating aswitch member to effect a series connection of the induction coil of theelectromagnet with a resistance before the armature reaches the fulllimit of its protrative excursion.
 4. Cutting apparatus according toclaim 3, characterized in that the induction coil, the armature and thetraction spring are so selected that, when the coil is connected inseries with said resistance, a current flows in the coil which, when thematerial to be cut has been separated completely, is just sufficient tohold fast the armature and the cutter in close contact with the magnetcore whereas, if the material has not been cut through completely, thecurrent is not sufficient because of the airgap existing due to thethickness of the uncut material between the armature and the core,wherefore the armature and the cutter are retracted into their originalposition by the spring and a repetition of the cutting movement occurs.5. Cutting apparatus according to claim 1, characterized by aring-shaped knife opened to one side which is arranged to cooperate withthe moveable cutter.